1,720,962 research outputs found
Lithological control and structural inheritance on faults growth in multilayer foreland sequences
Full text linkForeland sectors and foredeep-forebulge systems are affected, as the orogenic wedge migrates, by successive stages of stress states and tectonic deformation, resulting in the development of complex fault networks, even if characterized by limited deformation. The role played by structural inheritance and changes in stress field through time, in influencing the successive re-activations of fault segments, is still a topic to be thoroughly investigated. In this work, thanks to an extensive database made available by courtesy of Energean, we were able to investigate a foreland sector at the margin of the southern Apennines. By means of thickness analysis of the Neogene foredeep sequence and of displacement analysis along the fault network, we documented a shift from forebulge-related extension, in Zanclean, to a new tectonic phase, since Piacenzian, related to a strike slip stress field, possibly related to the activity of the Tremiti Fault Zone. We also characterized the geometry and connectivity of the cover-restricted faults, developing above propagating normal faults and observed a clear correlation between fault propagation tendency and lithological/mechanical layering within the cover units
The Impact of Polyphasic Extensional Tectonics on Fault Growth in the Central Apennines Foreland
No full textAnatomy and kinematic evolution of an ancient passive margin involved into an orogenic wedge (Western Southern Alps, Varese area, Italy and Switzerland)
Full text linkWe make use of own geological mapping, interpretations of seismic reflection profiles and deep geophysical data to build a lithospheric-scale cross-section across the European Western Southern Alps (Varese area) and to model a progressive restoration from the end of Mesozoic rifting to present-day. Early phases of Alpine orogeny were characterized by Europe-directed thrusting, whereas post-Oligocene shortening led to basement-involving crustal accretion accompanied by backfolding, and consistent with the kinematics of the adjoining Ivrea Zone. Wedging was favored by a significant component of reactivation of the inherited Adriatic rifted margin. Our results also suggest that, during the collisional and post-collisional tectonics, lithosphere dynamics drove diachronically the onset of tectonic phases (i.e., wedging and slab retreat), from east to west, across the Western Southern Alps
Scaling relationships and permeability structures of fault zones crosscutting tight Cretaceous platform carbonates (Murge Plateau, southern Italy)
No full textFault zones may exert a first-order control on fluid flow by acting either as a barrier and/or conduit in the
subsurface. Faults often include highly fractured damage zones encompassing cataclastic bodies (fault core) where
most of the deformation is localized. Especially in tight carbonates, both porosity and permeability significantly
increase within the fault damage zones, while the fault cores behave as a hydraulic barrier for cross-fault fluid
flow. The general validity of this hydraulic-deformational characterization of fault zones is influenced by several
factors including displacement distribution, fault geometry, modalities of fault propagation, fault slip direction,
mechanical rock properties and environmental conditions of deformation (mainly lithostatic burial and pore fluid
pressure).
In order to investigate the inner structure of tight platform carbonates, and hence gain new insights on the related
fault permeability, we study the fault dimensional parameters (i.e. damage zone and core thickness variations
relative to the amount of displacement) of different types of faults cropping out in the Murge Plateau, southern
Italy. The Murge Plateau represents the Plio-Pleistocene foreland of the South-Apennines orogenic belt which is
characterized by a relatively-thick lithosphere and a little deformed sedimentary cover. The outcrops in Murge
Plateau are good analogues of the Upper Cretaceous carbonate systems of the peri-Adriatic area that represent
important hydrocarbon reservoirs in southern Italy.
In this work, we compute the scaling relationships between fault dimensional parameters and the cumulative
frequency distributions of the fault-related fracture networks (i.e. spacing and opening). The scaling relationships
are fitted by power-law, logarithmic or exponential relationships, in agreement with different degree of faults
development within the geo-structural contest of this sector of the Apenninic foreland. Based on the relative
thickness between fault damage zones and fault cores, we infer different permeability structures associated to the
studied faults. These last parameters are strongly affected by the presence of both sedimentary dykes, which include
large clasts of breccias, clay material and calcite, and karst that often is present within the fault damage zones
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Faults scaling relationships and permeability structures in Cretaceous Platform Carbonates (Murge Plateau, Southern Italy)
No full textThe Upper Cretaceous carbonates cropping out in the Murge Plateau are good analogues of the fractured and faulted carbonate oil reservoirs of southern Italy. For this reason, a detailed field analysis focused on
structural architecture of fault and fracture networks has been carried out in the Murge Plateau. The well-bedded carbonates exposed there are crosscut by a set of bed-parallel stylolites and two sets of bed perpendicular cross-orthogonal joints/veins. These structural elements were likely formed under vertical loading during burial diagenesis and flexure of the Apulian foreland of the Southern Apennines fold-and thrust belt. Bed-parallel stylolites and bed-perpendicular cross-orthogonal joints/veins represent the background deformation that was overprinted by the fault-related localized deformation. The fault sets documented in the study area are arranged in two kinematically-compatible fault networks. The first one is made up ofWNW-ESE and NNW-SSE oriented strike-slip faults, right- and left-lateral, respectively, and NWeSE oriented normal faults. The second fault network consists of WNW-ESE oriented left-lateral strike-slip faults, and NEeSW oriented normal faults. First, both architecture and dimensional parameters of the fault and fracture networks have been characterized and computed by means of statistical analysis. Then, the permeability structures associated to the aforementioned networks have been assessed in order to determine the role exerted by fault architecture and dissolution/cementation processes on the fluid storage and migration pathways within the studied platform carbonates. Network 1 faults show a quite variable fluid behavior, in which the fluid flow is strongly affected by inherited structural elements and karst dissolution, whereas network 2 faults show a more uniform, fluid conduit behavior
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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